Screw driver



'w. L. McLE'AN.

SCREW DRIVER. ARRLICATION FILED MAY 24. I920.

INVENTOR. F11!- E]: L, 192.1. mm,

ClQ-(W I A TTORNEY' Patented May 9, 1922.

earner scnnw nerves.

Application filed May 24,

Z 0 all whom it may concern:

Be it known that I, WARREN L. Molinnia, a citizen of the United States, residing at the city and county of San Francisco and State of California, have invented anew and useful Improvement in Screw Drivers, of which the following is a specification.

This invention relates to a screw driver and especially to a screw driver of the mechanical or spiral shaft actuated type.

One of the objects of the present invention is to provide a simple, substantial, cheaply manufactured screw driverin, which rotary movement is transmitted to the bit or chuck by means of a spiral shaped shaft and a nut co-operating therewith.

Another object of the invention is to provide a novel form of handle and casing for the support and reception of the spiral shaft and into which it is adapted to move telescope-wise and in conjunction therewith a springand plunger so arranged as to normally project and rotate the spiral shaft with relation to the handle, the casing and nut.

Another object of the invention is to pro vide a manually operated mechanism for locking the spiral shaft against projection with relation to the handle and easing when the tool is not in use.

Further objects will hereinafter appear.

The invention consists of the parts and the construction, combination and arrangement of parts as hereinafter more fully described and claimed, having reference to the accompanying drawings, in which-.

Fig. 1 is a side elevation of the screw driver showing the spiral shaft projected.

Fig. 2 is a central vertical longitudinal section of the screw driver showing. the spiral shaft in retracted position within the casing.

Fig. 3 is a detail perspective view of the locking mechanism whereby the spiral shaft is secured against projection.

Fig. 4 is a detail view of the locking mechanism showing the spiral shaft retracted and locked against projection.

Fig. 5 is a cross section on line 5-'5, Fig. 2.

Referring to the drawings in detail, A indicates a tubular casing on the upper end of which is secured a. handle 2. Formed a short distance below the handle on the tube A is an annular shoulder 3, and turnably mounted on the tube between the shoulder and the end of the handle 2 is a collar 4.

Specification of Letters Patent.

Patented May 9, 1922.

1920. Serial No. 3,228,617.

Suitably secured in the lower end of the tube s a nut 53, in which is formed a square opening 6, and adapted to enter the tube and pass through the opening in the nut 5 is a spiral shaped shaft 7, on the inner end of which is secured a plunger 8. Forming a closure for the upper end of the tube is a plug 9 and extending through the handle, the tube ant the plug is a locking pin 10. This pin serves two functions, first that of securing the plug 9, and secondly that of securing the handle 2, both against endwise and turning move ment upon the tube A. interposed between the plug and the plunger 8 is a spring. 11. This spring is provided for the purpose of normally exerting an endwise pressure on the plunger 8 and the "spiral shaft 7, the

spring being sufficiently longand having sufiicient tension to normally project the spiral shaft as shown in Fig. 1. Secured on the lower end of the spiral shaft 7 is a standard form of screw chuck 12, which is provided for the reception of a screw driving bit, a drill or whatever tool may be'employed. 1

v Turnably mounted on the lower end of the tube is a locking collar 14. This collar is slotted near its upper end as at 15 and a pin 16 projecting therethrough secures the col lar against endwise movement upon the tube and also limits the turning movement of the collar with relation thereto. Formed on the lower end of the collar is an annular inturned shoulder 17, a portion of which is cut away, as at 18', to permit a pin 19 to pass therethrough. This pin is secured on the lower end of the spiral. shaft at a point adj acent the chuck and is provided for the purpose of engaging the locking collar 1.4 and thereby securing the spiral shaft against projection when the tool is not in operation.

In actual operation with a bit or drill secured in the chuck 12, it is possible to impart a rotary movement thereto by first propecting the spiral shaft 7. This is accomplished by turning the collar'14- until the recess 18 registers with the pin 19. This causes a release of the locking collar with relation to the pin 19, and thereby permits projection of the spiral shaft as this is normally subjected to the pressure or endwise thrust of the spring 11.

The tool held by the chuck 12, for instance a screw driving bit, is next brought into engagement with the screw to be inserted and t e chuck 12 is simultaneously held loosely in one hand while a downward pressure is exerted on the handle 2 by the other handle. This pressure causes the tube A, the handle 2 and the nut 6, secured in the tube, to travel downwardly on the spiral. shaft, and as the handle, the tube and the nut is secured in the hand against rotary movement, it is obvious that a rotary movement will be transmitted to the spiral shaft, the chuck 12 and the screw bit carried thereby, the spring 11 being at the same time compressed. One or two revolutions isin this manner transmitted to the screw driving bit and it is of course necessary to impart several additional revolutions before the screw is driven home. It is therefore necessary to return the tube, the nut and the handle to the raised position shown in Fig. 1 so that a second downward movement may be transmitted thereto. This is accomplished by grasping the chuck l2 and thereby securing the spiral shaft against rotation, and simultaneously grasping the collar 4, which is turnably mounted on the tube. The downward pressure exerted by the operator is now released and the nut, the tube and the handle is permitted to be raised by the action of'the spring 11. The

a handle, the tube and the nut will now rotate the downward movement as it is then as they are only held by the collar 4- and the chuck and spiral shaft are held against rotation by the other hand. In other words the tube and handle freely rotate within the hand of the operator during the 'upward movement of the same, butare tightly grasped and held against rotation during desired to impart a rotary movement to the spiral shaft, the chuck and the tool carried thereby. This cycle of operation is repeated as many times as is necessary or until the screw is driven home.

From the foregoing it can be seen that the spiral shaft, the chuck and the tool carried thereby are automatically projected with relation to the tube and the handle, and that rotary movement is simultaneously transmitted thereto by the nut 63. Again it may be stated that during the operation of the tool, the spring serves the function of automatically raising the nut, the tube and the handle to return the same to working position as turning movement should only be transmittedto the shaft 7 during downward movement of the nut.

If the screw driver is to be placed in a tool box, or otherwise disposed of when not 1 1n use, it is obvious that shortening of the screw driver as a whole would be convenient changes in form and as considerable less space would be occupied. l have for this reason provided the locking nut shown at l l and the pin 19. This permits the spiral shaft to be retracted with relation to the tube, or to be moved telescopewise within the same until the pin 19 passes through the slot 18. It is here secured by merely turning the collar until the pin 16 engages the opposite end of the slot 15. The shoulder 17 on the locking collar will during this turning movement pass in under the pin 19 and will gether with the spiral tion. collar 14: brings the slot 18 into register with the pin 19 and thereby permits the spring 11 to automatically and instantly project the spiral shaft and chuckcarr'ied thereby.

While certain features of the present invention are more or less specifically illustrated, I wish it understood that various proportion may be resorted to within the scope of the appended claims, similarly that the materials and finish of the several parts employed may be such as the experience and judgment of the manufacturer may dictate or varying conditions may demand.

Having thus described my invention, what I claim and desire to secure by Letters Patent isshaft, against projecl. In a screw driver of the character described the combination with a spiral tool shank, a tube casing having a threaded connection with the shank to rotate the same by relative endwise movement and a handle secured to the tube of an annular shoulder formed on the tube below the handle and a collar .turnably mounted on the tube between said shoulder and the handle.

2. In a screw driver of the character described the combination with a spiral tool shank, a tube casing having a threaded connection with the shank to rotate the same by relative endwise movement and a handle secured to the tube, of a collar turnably mounted on the casing below the handle and means securing said collar against enclwise movement upon the tube.

In testimony whereof I have hereunto set my hand in the Geo. J. BLACK,

thereby secure it, to-[ Conversely reverse movementof the presence of two subscribing 

